I am in the process of swapping the engine in my 90 GL1500 due to the dreaded 4th gear shift fork death rattle.My question is about the black rubber matt / cover that sits on top of the engine with a hole in the middle for the carbs to stick through.When I removed the cover it came out in pieces. The rubber had hardened from age and heat I guess.How important is this? if I don't replace it will I have problems with vapor lock? I am assuming it was put there to keep heat away from the carbs.

If you look up the local supplier for "hose and rubber", they should be able to get you a sheet of the proper rubber that will work.I'm not talking about the local auto store but a true industrial hose supplier.Measure the thickness and size you need or take them a piece and let them know it is for low temp heat shielding. You will have to cut the holes in it yourself.I deal with our local supplier all the time and a piece the size you need should be about $20.00 or less I would think.